Search Publications
Cometary Activity Discovered on a Distant Centaur: A Nonaqueous Sublimation Mechanism
Chandler, Colin Orion; Trujillo, Chadwick A.; Oldroyd, William J. +2 more
Centaurs are minor planets thought to have originated in the outer solar system region known as the Kuiper Belt. Active Centaurs enigmatically display comet-like features (e.g., tails, comae) even though they orbit in the gas giant region where it is too cold for water to readily sublimate. Only 18 active Centaurs have been identified since 1927 a…
The State of the Heliosphere Revealed by Limb-halo Coronal Mass Ejections in Solar Cycles 23 and 24
Gopalswamy, Nat; Akiyama, Sachiko; Yashiro, Seiji
We compare the properties of halo coronal mass ejections (CMEs) that originate close to the limb (within a central meridian distance range of 60°-∼90°) during solar cycles 23 and 24 to quantify the effect of the heliospheric state on CME properties. There are 44 and 38 limb halos in cycles 23 and 24, respectively. Normalized to the cycle-averaged …
Cool, Luminous, and Highly Variable Stars in the Magellanic Clouds from ASAS-SN: Implications for Thorne-Żytkow Objects and Super-asymptotic Giant Branch Stars
Drout, Maria R.; O'Grady, Anna J. G.; Kochanek, C. S. +9 more
Stars with unusual properties can provide a wealth of information about rare stages of stellar evolution and exotic physics. However, determining the true nature of peculiar stars is often difficult. In this work, we conduct a systematic search for cool and luminous stars in the Magellanic Clouds with extreme variability, motivated by the properti…
Dynamics of Late-stage Reconnection in the 2017 September 10 Solar Flare
Judge, Philip G.; Long, David M.; Matthews, Sarah A. +2 more
In this multi-instrument paper, we search for evidence of sustained magnetic reconnection far beyond the impulsive phase of the X8.2-class solar flare on 2017 September 10. Using Hinode/EIS, CoMP, SDO/AIA, K-Cor, Hinode/XRT, RHESSI, and IRIS, we study the late-stage evolution of the flare dynamics and topology, comparing signatures of reconnection…
Impact of Planetary Mass Uncertainties on Exoplanet Atmospheric Retrievals
Waldmann, I. P.; Tinetti, G.; Changeat, Q. +1 more
In current models used to interpret exoplanet atmospheric observations, the planetary mass is treated as a prior and is measured/estimated independently with external methods, such as radial velocity or transit timing variation techniques. This approach is necessary as available spectroscopic data do not have sufficient wavelength coverage and/or …
Completing the Census of AGN in GOODS-S/HUDF: New Ultradeep Radio Imaging and Predictions for JWST
Rieke, George H.; Alberts, Stacey; Nyland, Kristina +2 more
A global understanding of active galactic nuclei (AGN) and their host galaxies hinges on completing a census of AGN activity without selection biases down to the low-luminosity regime. Toward that goal, we identify AGN within faint radio populations at cosmic noon selected from new ultradeep, high-resolution imaging from the Karl G. Jansky Very La…
Elemental Abundances in M31: [Fe/H] and [α/Fe] in M31 Dwarf Galaxies Using Coadded Spectra
Gilbert, Karoline M.; Majewski, Steven R.; Beaton, Rachael L. +5 more
We present chemical abundances of red giant branch (RGB) stars in the dwarf spheroidal (dSph) satellite system of Andromeda (M31), using spectral synthesis of medium-resolution (R ∼ 6000) spectra obtained with the Keck II telescope and Deep Imaging Multi-Object Spectrometer spectrograph via the Spectroscopic and Photometric Landscape of Andromeda'…
Stellar Spins in the Open Cluster NGC 2516
Healy, Brian F.; McCullough, P. R.
Measuring the distribution of stellar spin axis orientations in a coeval group of stars probes the physical processes underlying the stars' formation. In this paper, we use spectrophotometric observations of the open cluster NGC 2516 to determine the degree of spin alignment among its stars. We combine TESS light curves, ground-based spectroscopy …
A 60 kpc Galactic Wind Cone in NGC 3079
Bregman, Joel N.; Yukita, Mihoko; Ptak, Andrew F. +3 more
Galactic winds are associated with intense star formation and active galactic nuclei. Depending on their formation mechanism and velocity, they may remove a significant fraction of gas from their host galaxies, thus suppressing star formation, enriching the intergalactic medium, and shaping the circumgalactic gas. However, the long-term evolution …
NuSTAR Discovery of a Compton-thick, Dust-obscured Galaxy: WISE J0825+3002
Tanimoto, Atsushi; Ueda, Yoshihiro; Kawamuro, Taiki +6 more
We report the discovery of a Compton-thick (CT), dust-obscured galaxy at z = 0.89, WISE J082501.48+300257.2 (WISE 0825+3002), observed by the Nuclear Spectroscopic Telescope Array. X-ray analysis with the XCLUMPY model revealed that hard X-ray luminosity in the rest-frame 2-10 keV band of WISE 0825+3002 is L X (2-10 keV) = {4.2}-1.…